Aging is a complex biological process. The identification and characterization of the mechanisms controlling the aging process has proven to be an elusive task. Genetic approaches are often used to gain insight into complex biological phenomena, primarily because of their ability to uncover a causal pathway leading from the gene to the phenotype, and vice-versa. We are involved in the genetic analysis of extended longevity in Drosophila melanogaster. We have chosen to examine genes that lengthen life rather than those that shorten life in the well documented belief that longevity extension genes are more likely to be affecting processes important to the normal aging situation. Our construction and analysis of genetically based long lived strains has allowed us to develop a powerful genetic means of identifying both the structural and regulatory genes involved in the extension of longevity. Our experimental system allows us to manipulate environmental and genetic variables, and thereby permitted us to identify the existence of several early-acting, regulatory events critical to the extended longevity phenotype (ELP). The most important of these events is the up- regulation of specific antioxidant defense system (ADS) genes in the young adult, which appears to be required for the subsequent delayed onset of senescence characteristic of the ELP. We have also developed rapid and accurate bioassays for longevity which are well suited for screening tests. By arranging these various components in a logical manner, we have been able to devise an insertional mutagenesis protocol and a four-step screening procedure which will permit the identification of regulatory and structural genes critical to the coordinated up regulation of the ADS genes and/or to the expression of the ELP. The specific aims of the research described in this proposal are to: a. identify single P-element insertional mutations which will allow us to identify regulatory genes controlling both the age-specific coordinated up-regulation of the ADS genes as well as longevity; b. identify regulatory genes controlling longevity through mechanisms other than the ADS system; and c. to use standard procedures to isolate, characterize, and identify these LAGs, and thereby gain some insight into the nature of the genetic mechanisms regulating the expression of the ELP. Molecular genetic studies on this Drosophila system may give us insight into the ADS gene regulatory mechanisms as well as some insight into the animals' ADS-dependent CNS aging mechanisms, both of which may be translated into mammalian and human studies. Since an estimated 71% of Drosophila genes have human counterparts, our strategy represents a cost- effective and ethically acceptable means of investigating these basic biological processes with implifications for human health and longevity.